1. Field of the Invention
The present invention relates to a cold-accumulating type air conditioning system for a vehicle, provided with a cold accumulator cooled by cold air after passing through a cooling heat exchanger. This air conditioning system is suitably used for a vehicle which temporarily stops its engine, which is used as the drive source of a compressor when the vehicle stops.
2. Description of Related Art
In recent years, in order to protect the environment, a vehicle (economically running vehicle, hybrid vehicle, or the like) automatically stops its engine when the vehicle stops such as when waiting for a change of a traffic signal, and there is a tendency to increase the number of these vehicles which stops their engine at the stoppage of the vehicle.
In an air conditioning system for a vehicle, a compressor of a refrigerating cycle is generally driven by a vehicular engine. Therefore, in the economically running vehicle or the like described above, at the stoppage of the vehicle, such as when waiting for the change of the traffic signal, the compressor is also stopped. Accordingly, an increase in the temperature of a cooling heat exchanger (evaporator) is increased, an air temperature blown into a passenger compartment is increased, and therefore, a reduction in the cooling of a passenger in the passenger compartment is experienced.
JP-A-2000-38015 describes a cold-accumulating type air conditioning system for a vehicle provided with a cold accumulator. In this system, the cold accumulator accumulates cold at time of operation of a compressor, and air blown into the passenger compartment is cooled by the cold accumulator during the stoppage of the compressor (at time of stoppage the cooling operation of a cooling heat exchanger). However, the cold accumulator is integrally formed with an air mixing door for adjusting an air volume ratio between cold air passing through a bypath passage while bypassing a heating heat exchanger, and hot air passing through the heating heat exchanger. In this case, since the cold accumulator is integrally rotated with the air mixing door, an exposed condition of cold air to the cold accumulator is changed by the rotation of the air mixing door, and a change in the capability of the cold accumulation of the cold accumulator is experienced. Further, since the cold accumulator is provided on a surface of the air mixing door at a side of the bypath passage, when the air mixing door is displaced to the closing side of the bypath passage, the capability of the cold accumulation of the cold accumulator is lowered.
On the other hand, in JP-A-H1-153321, there is proposed a cold accumulator which is arranged in an air passage between a cooling heat exchanger and a heating heat exchanger. Further, a refrigerant pipe of a refrigerant cycle is disposed within the cold accumulator, and the cold accumulator is cooled by the cold of the refrigerant pipe. However, since the refrigerant pipe is arranged in the cold accumulator, a construction of the cold accumulator becomes complicated, and thus leads to an increase in cost.